This invention relates to a structure and manufacturing method of a semiconductor gauge using a diffused resistor, which can be used for various acceleration sensor pressure sensor, etc.
A strain gauge is used to detect acceleration and pressure in the prior art and there are various types in the strain gauge. The strain gauge using a semiconductor single crystal is used in many cases, which detects the changes in force applied utilizing the piezoelectric resistance effect of the semiconductor as variation in electric resistance. There are a bulk type gauge and a diffused type gauge in the semiconductor strain gauge using the piezoelectric resistance effect and it is necessary to apply manufacturing work on the semiconductor substrate because the semiconductor substrate itself becomes a gauge in each type.
FIG. 7 shows the structure of a diffused type gauge used commonly and (a) is a vertical sectional view and (b) is a plan view viewed from an arrow A-A line direction in (a). A diffused resistor 2 of opposite conduction type is formed, diffusing a type P impurity into the surface of type N single crystal silicone substrate 1. A surface of the diffused resistor 2 is protected with oxide film 3 such as SiO2, which is an insulated film and a positive (+) electrode 4 and a negative (−) electrode 5 are formed by metallic film of aluminum and the like after etching a part of the oxide film 3. It is not necessary to process the semiconductor substrate mechanically when the resistance layer is formed on the type N single crystal silicone substrate 1 as the semiconductor substrate by diffusion.    [Patent document 1] U.S. Pat. No. 6,635,910    [Patent document 2] JP, 2001-264188, Publication of unexamined patent applications    [Patent document 3] JP, 2004-531699, PCT Publication of unexamined patent applications